JPH0452067B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a current lead for a cryogenic device that requires high strength and supplies current from a normal temperature part to a low temperature part, such as a current lead of a rotor of a superconducting rotating electrical machine. Regarding leads.

[Technical background of the invention and its problems]

Conventionally, when supplying a large current from a room-temperature part to a low-temperature part, especially in the liquid helium temperature range, the current lead was connected to a helium evaporator to prevent conduction heat from the room-temperature part and joule heat caused by the current from penetrating into the low-temperature part. Cooling with gas, etc. is performed. In this early version, the outer circumference of the cylindrical current lead was simply cooled with helium evaporation gas, but the cooling performance was not very good, so a heat exchanger was installed inside the current lead. However, various proposals have been made. The heat exchanger in this current lead is often constructed by arranging a large number of cooling fins or using a mesh-like electrical conductor. Therefore, although such current leads provide good performance for static cryogenic equipment,
In cases where strong centrifugal force is applied, such as in the current lead of the rotor of a superconducting rotating electric machine, the mechanical strength is insufficient.

[Purpose of the invention]

An object of the present invention is to provide a current lead for a cryogenic device that is mechanically strong and has good cooling performance.

[Summary of the invention]

In the present invention, in a current lead for a cryogenic device that supplies current from a normal temperature part to a low temperature part,
A large number of pipes made of conductive metal are inserted into an outer cylinder made of conductive metal, and the air space between the pipes in the outer cylinder and the pipes in the outer cylinder is
The pipe is densely filled with conductive filling material, the inside of the pipe is used as a refrigerant flow path, and the room temperature side terminal and the low temperature side terminal are connected to both ends of the outer cylinder. The dense structure increases mechanical strength, and the cooling performance is improved by using the inside of many pipes as refrigerant channels.

[Embodiments of the invention]

Example 1 A first example of the present invention will be described below with reference to FIGS. 1 and 2.

A large number of pipes 1 (37 in Fig. 2) made of conductive metal and having a regular hexagonal cross-sectional shape are bundled together with no spaces between them, and inserted into a cylindrical outer cylinder 2 made of conductive metal. The space between pipe 1 in 2 is densely filled with molded conductive filling member 3. At this time, the outer periphery of the pipe 1, the inner periphery of the outer cylinder 2, and the outer periphery of the filling member 3 are plated with solder (silver solder may also be used). The tube 2 and the filling member 3 are integrated to improve electrical and thermal conduction and to be mechanically strong. The inside of the pipe is a refrigerant passage 4. A normal temperature side terminal 15 and a low temperature side terminal 6 are connected to both ends of the outer cylinder 2. An insulating coating 7 is provided on the outer periphery of the outer cylinder 2.

Next, the effect will be explained.

Current flows through the pipe 1, the outer cylinder 2, and the filling member 3. Therefore, Joule fever occurs in this area,
Furthermore, the heat conducted from the normal temperature side terminal 5, which is the normal temperature part, to the low temperature side terminal 6, which is the low temperature part, is also conducted through the pipe 1, the outer cylinder 2, and the filling member 3. In order to prevent this heat from entering the low temperature section, a refrigerant such as helium gas is passed through the refrigerant passage 4 of the pipe 1 to remove heat from the inner surface of the pipe 1. This heat exchange effect may be slightly inferior in the case of the current lead of the same length compared to the conventional example using a large number of fins because the area of the heat exchange part is smaller in this example. If the number of current leads is increased or the length of the current leads is increased, a sufficient cooling effect will be achieved. Also, pipe 1
Since it is closely integrated with the outer cylinder 2 and the filling member 3, heat from the outer cylinder 2 and the filling member 3 is also efficiently removed. Note that the shape of the cooling passage 4 of the pipe 1 does not need to be the same as the regular hexagonal shape of the outer shape of the pipe 1; for example, it may be circular, or it may have an uneven inner surface to enhance the cooling effect. . and,
In the current lead of this embodiment, since the pipe 1 is a straight pipe, there is an advantage that pressure loss in the flow of refrigerant is small.

In addition to the cooling effect described above, the current lead of this embodiment is mechanically very strong. This is because a large number of pipes 1 and the filling member 3 are tightly packed and integrated into the outer cylinder 2. Therefore,
It is suitable for current leads placed in high centrifugal force fields, such as the current leads of the rotor of superconducting rotating electric machines, and for current leads that are subject to large mechanical forces.

Furthermore, since the outer shape of the pipe 1 is a regular hexagon, the number of adjacent pipes other than the outermost pipe is 6, and when bundled, the mutual pipe positions are not shifted and the bundle is stable. The shape is also fixed. It is easier to handle the current lead if its cross-sectional shape is circular, but for that purpose, it is sufficient to insert the pipe 1 and the filling member 3 together into a circular bundle into the cylindrical outer tube 2. It is extremely easy to manufacture.

Embodiment 2 FIG. 3 shows the embodiment of FIG. In this example, the cross-sectional outline of the pipe 1 is square, and the other aspects are the same as in Example 1.

In this case, since the cross-sectional outer shape of the pipe 1 is square, the positions of adjacent pipes are likely to shift, making it slightly more difficult to bundle the pipes into a circular shape than the hexagonal pipes 1 of the first embodiment. However, by using an appropriate jig (not shown) or after inserting the pipe 1 into the outer cylinder 2,
If the molten conductive metal is poured into the air and then cooled and solidified to form the conductive filling member 3,
It can be manufactured without being too expensive. Other effects are the same as in Example 1.

Embodiment 3 FIG. 4 shows a third embodiment. This is pipe 1
The conductive filling member 3 was made by pouring molten conductive metal into the cavity in the outer cylinder 2 and solidifying it, and the other aspects were the same as in Example 1.

The circular pipe 1 can be manufactured at low cost because a ready-made copper pipe or the like can be used. Although the arrangement of the pipes 1 tends to be irregular, other effects are the same as in the first embodiment.

Note that the shapes of the pipe 1, outer cylinder 2, etc. may be other shapes than those of the above embodiments.

〔Effect of the invention〕

As explained above, according to the present invention, a large number of pipes made of conductive metal are inserted into an outer cylinder made of conductive metal, and the spaces between the pipes in the outer cylinder are tightly filled with a conductive filling member. Since it is filled, it is mechanically extremely strong, and since the inside of the pipe is used as a refrigerant passage, it is possible to provide a current lead for a cryogenic device with good cooling performance.

[Brief explanation of the drawing]

FIG. 1 is a cutaway elevational view of essential parts showing the first embodiment of the current lead for cryogenic equipment of the present invention, and FIG.
FIGS. 3 and 4 are enlarged cross-sectional views taken along the - line in the figure, and are cross-sectional views showing second and third embodiments. 1...Pipe, 2...Outer cylinder, 3...Filling member,
4... Refrigerant passage, 5... Normal temperature side terminal, 6... Low temperature side terminal.

Claims (1)

[Claims] 1. In a current lead for a cryogenic device that supplies current from a room-temperature part to a low-temperature part, a number of pipes made of conductive metal are inserted into an outer cylinder made of conductive metal, and the pipes inside the outer cylinder are A current lead for a cryogenic device, characterized in that the space between the pipe and the pipe is densely filled with a conductive filling member, the inside of the pipe is used as a refrigerant flow path, and a normal temperature side terminal and a low temperature side terminal are connected to both ends of the outside surface. . 2. The pipes have a regular hexagonal cross-sectional shape and are arranged without any voids between them, the outer tube is cylindrical, and the filling material used to fill the void between the pipe and the outer tube is a pre-formed material. Claim No. 1
Current lead for cryogenic equipment as described in section. 3. Claim 1 or 2, characterized in that the current lead is disposed within the rotor of a rotating electric machine.
Current leads for cryogenic equipment as described in section.